1. FIELD OF THE INVENTION
The present invention relates generally to an interface between a liquid chromatograph and a mass spectrometer and more particularly to an interface for conducting the liquid effluent from the chromatograph to the spectrometer. Apparatus for continuously concentrating the effluent is also provided.
2. DESCRIPTION OF THE PRIOR ART
Several attempts have been made to provide an interface between a liquid chromatograph and a mass spectrometer. Additionally, attempts have been made to concentrate a liquid stream by evaporating the solvent from the stream.
McFadden, U.S. Pat. No. 4,055,987, discloses a liquid chromatograph/mass spectrometer interface for permitting the introduction of a solution from the chromatograph to the spectrometer. A metallic ribbon in the form of a loop is moveable and is utilized to deliver the liquid stream to the spectrometer, and a heat source is provided for heating the stream in order to achieve preliminary evaporation.
McLafferty et al., U.S. Pat. No. 3,997,298, discloses an apparatus and method for continuously introducing an eluted effluent from a liquid chromatograph into the ionization chamber of a mass spectrometer. The apparatus includes a restricted capillary tube for introduction of the mixture into the chamber and is designed to slow the entrance of solution into the spectrometer to a small percentage of the normal flow rate of the effluent.
Miyagi et al., U.S. Pat. No. 4,112,297, discloses a liquid chromatograph/mass spectrometer interface for introducing a nebulized effluent sample to the ion source of a mass spectrometer. The interface includes an evaporator having a heater for evaporating only the solvent in the nebulized effluent from the chromatograph.
Other prior art interfaces are disclosed for transporting a liquid stream from the chromatograph by means of a pretreated conveyor belt as well as by vaporizing the solvent by heating, vacuum, and/or an inert gas flow. Such teachings can be found in German Pat. Nos. 2,654,057 and 2,811,300.
Other devices broadly disclose the use of heating for evaporating a solvent. Parkhurst, U.S. Pat. No. 3,896,661, discloses a method and apparatus for coupling a thin-layer chromatography system with a mass spectrometer. The analytes in the chromatograph are sublimed by heat into a spectrometer ion source.
Gunew et al., U.S. Pat. No. 3,929,004, discloses a device for conveying a liquid stream used in conjunction with an analysis of the material suspended within the stream. The stream is retained by a wire mesh conveyor and is heated in order to volatilize the liquid and leave a residue on the conveyor, which residue is then transported into a gas chromatography mass flow detector.